If you have proof that it's yours (e.g. a copy of the death certificate and will leaving it to you, and possibly also its original receipt ; ask them what they might want to see before they might help) you could try a Genius Bar appointment at an Apple Store or contacting iTunes Support and see if they can/will activation lock from it
You will need to contact AppleCare to guide you on this.
In a nutshell:
As Apple values privacy and security, the previous account of the deceased will most likely not be unlocked, so there won't be able to access any data from previous however
once your request is approved you will be able to reset the iPad and use it with your own Apple ID.
The request will need to be escalated to AppleCare;
1.Original proof of purchase to have the activation lock removed.
2.You will a death certificate and a court order appointing you as the legal represenative
I am not sure the Apple Store will be able to assist
More from AppleCare
Question: Activation Lock